Heretofore, X-ray images using films have widely been used in medical settings. However, the X-ray image using a film provides analog image information, and thus digital radiation detection devices such as computed radiography (CR) and flat panel radiation detection devices (flat panel detectors: FPDs) have recently been developed.
In a flat panel X-ray detector (FPD), a scintillator panel is used for converting radiation into visible light. The scintillator panel contains an X-ray phosphor such as cesium iodide (CsI) and the X-ray phosphor emits visible light in response to applied X-ray, and the emitted light is converted into an electric signal by a thin film transistor (TFT) or a charge-coupled device (CCD) to thereby convert X-ray information into digital image information. However, the FPD has a problem such as a low S/N ratio. In order to increase the S/N ratio, there have been proposed methods of irradiating with X-ray from a light detector side (Patent Literatures 1 and 2), and also there have been proposed methods of filling cells divided by a barrier rib with an X-ray phosphor, so as to reduce an influence of the scattering of visible light due to the X-ray phosphor (Patent Literatures 3 to 6).
The method which has hitherto been used as a method for forming the barrier rib is a method of etching a silicon wafer, or a method in which a glass paste as a mixture of a pigment or a ceramic powder and a low melting point glass powder is pattern-printed in multiple layers using a screen printing method, and then fired to form a barrier rib. However, in the method of etching a silicon wafer, the size of a formable scintillator panel is limited by the size of the silicon wafer, and a scintillator panel having a large size of 500 mm square could not be obtained. A plurality of small-size panels should be arranged for making a large-size panel. However, it is difficult to produce the scintillator panel in view of accuracy, and a large-area scintillator panel was scarcely produced.
In the multi-layer screen printing method using a glass paste, it is difficult to process with high accuracy due to a dimensional variation of a screen printing sheet, or the like. When multi-layer screen printing is performed, a definite barrier rib width is required for increasing the strength of a barrier rib in order to prevent destructive defects of the barrier rib. However, if the width of the barrier rib increases, a space between barrier ribs becomes relatively small, so that a volume available for filling an X-ray phosphor decreases, and the filling amount is not uniform. Therefore, a scintillator panel obtained in this method has a disadvantage such as a decrease in luminescence or occurrence of luminous unevenness because of too small amount of an X-ray phosphor. This disadvantage of flexibility is an obstacle to formation of clear images in photographing at a low dose.